Lapatinib ditosylate, N-[3-chloro-4-[(3-fluorophenyl)methoxy]phenyl]-6-[5-[(2-methylsulfonylethylamino)methyl]-2-furyl]quinazolin-4-amine ditosylate, has the following chemical structure:

Lapatinib ditosylate is currently marketed in the United States under the tradename TYKERB® by GlaxoSmithKline. It was approved by the FDA as a drug for use in patients with advanced metastatic breast cancer.
Lapatinib ditosylate is described in PCT publications WO1999/035146, WO2002/002552, WO2005/046678, WO2006/113649, WO1998/002437, WO2001/004111, WO1996/009294, WO2002/056912, WO2005/105094, WO2005/120504, WO2005/120512, WO2006/026313, and WO2006/066267.
Two polymorphs of lapatinib ditosylate, anhydrous and monohydrate forms are described in U.S. Pat. No. 7,157,466 (WO 2002/002552).
The present invention relates to the solid state physical properties of lapatinib ditosylate. These properties can be influenced by controlling the conditions under which lapatinib ditosylate is obtained in solid form. Solid state physical properties include, for example, the flowability of the milled solid. Flowability affects the ease with which the material is handled during processing into a pharmaceutical product. When particles of the powdered compound do not flow past each other easily, a formulation specialist must take that fact into account in developing a tablet or capsule formulation, which may necessitate the use of glidants such as colloidal silicon dioxide, talc, starch or tribasic calcium phosphate.
Another important solid state property of a pharmaceutical compound is its rate of dissolution in aqueous fluid. The rate of dissolution of an active ingredient in a patient's stomach fluid can have therapeutic consequences since it imposes an upper limit on the rate at which an orally-administered active ingredient can reach the patient's bloodstream. The rate of dissolution is also a consideration in formulating syrups, elixirs and other liquid medicaments. The solid state form of a compound may also affect its behavior on compaction and its storage stability.
These practical physical characteristics are influenced by the conformation and orientation of molecules in the unit cell, which defines a particular polymorphic form of a substance. These conformational and orientation factors in turn result in particular intramolecular interactions such that different polymorphic forms may give rise to distinct spectroscopic properties that may be detectable by powder X-ray diffraction, solid state 13C NMR spectrometry and infrared spectrometry. A particular polymorphic form may also give rise to thermal behavior different from that of the amorphous material or another polymorphic form. Thermal behavior is measured in the laboratory by such techniques as capillary melting point, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and can be used to distinguish some polymorphic forms from others.
The discovery of new polymorphic forms of a pharmaceutically useful compound provides a new opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for designing, for example, a pharmaceutical dosage form of a drug with a targeted release profile or other desired characteristic. There is a need in the art for additional polymorphic forms of lapatinib ditosylate.